“@justinbieber you’re crazy and nonna says thank you, she loves you,” the 20-year-old Sam & Cat actress captioned the photo on Twitter.
Ariana also shared a picture of her adorable grandparents meeting Justin during his fan meet and greet. Check out the photos below!
“@ArianaGrande post that pic and tell your grandma she is a cutie,” Justin later tweeted Ariana.
TELL JJJ: Are you going to see Justin Bieber and Ariana Grande on tour?